Knife sheath



FIG. 1 is a perspective view of a knife sheath showing my new design;

FIG. 2 is a left side elevation thereof;

FIG. 3 is a front elevation thereof;

FIG. 4 is a right side elevation thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof; and

FIG. 7 is a rear elevation thereof. 

The ornamental design for a knife sheath, as shown. 